In the manufacture of synthetic textile fibers and yarns, it is well known to process filamentary material in tow form, i.e., a relatively large continuous band or cable of multiple filaments, particularly in the manufacture of staple fibers wherein the multifilament tow is subsequently cut into staple length for use in nonwoven or synthetic blend fabric products. In such processing, the tow band is often subjected to a mechanical crimping operation, after which it is subjected to a heat setting operation under relaxed conditions. Typically, this is accomplished by continuously depositing the flattened, crimped band of tow, immediately after crimping, in relaxed, overlapping loops or layers across the surface of a horizontally moving conveyor which transports the layers through a heating oven for thermal treatment, such as heat setting. After thermal treatment, the band of tow is continuously longitudinally withdrawn from the surface of the moving conveyor for further processing or collection. In continuously depositing and recovering the tow from the moving conveyor, care must be taken to ensure that the tow is deposited on and withdrawn from the conveyor surface with minimum disturbance, displacement, or entanglement of the overlapping layers of tow. If the tow is deposited directly across the moving conveyor from a feed point such that preceding layers in the direction of movement of the conveyor normally underlie next succeeding layers, it can be appreciated that during tow removal from the conveyor after treatment, the tow will always be longitudinally withdrawn from an underlying layer of the overlapped layers on the conveyor surface. Such a procedure causes disruption, displacement, or entanglement of the filamentary tow, with consequent undesirable results in processing.
To reduce disruption or entanglement of the tow layers during removal from the conveyor, certain apparatus has been employed for inverting, or reversing, the lay of the overlapping layers of tow deposited on the conveyor such that preceding layers of tow on the conveyor are reoriented to lie on top of next succeeding layers. Such tow-inverting apparatus, as far as known in the prior art, consist of moving belts or drums which convey the layers of tow through a curvilinear path to reverse their direction of overlap on the moving conveyor so that topmost layers of tow are first withdrawn from the conveyor after thermal treatment. One such device, manufactured by Neumag Division of Gruppe Deutsche Babcock of Germany, comprises a moving conveyor belt and rotating drum arrangement which are spaced apart to form a moving feed trough into which a continuous length of tow is deposited in successive overlapping layers. The layers are transported by the moving drum and belt surfaces in a curvilinear path to reverse the direction of overlap of the layers and locate each preceding layer on top of the next succeeding layer in the direction of conveyor belt movement. In this way, continuous removal of the tow from the conveyor after the thermal treatment draws consecutive topmost layers of the overlapping tow from the belt, rather than underlying layers of the tow, as would be the case if the lay of the tow were not inverted.
The above-described moving belt and drum type tow inverter apparatus has certain drawbacks and disadvantages. The layers and individual filaments processed therein are often disturbed, displaced or otherwise entangled during passage through the inverter. In addition, the moving belt/rotating drum type tow inverter is of considerable size and expense, with numerous moving parts, adding to capital outlay as well as normal operating expenses of the tow processing operation.